Want a free cup of Starbucks? Why not use Jonathan Stark’s Starbucks app to redeem yourself a couple cups of coffee? Wait, how does that work? Well it appears that Jonathan Stark, a mobile app consultant, gave away his Starbucks mobile-app code and basically let everyone in the US who wished to get a free cup of Starbucks, to have one on him.

He started with $30 in credit via the Starbucks app on the iPhone. He then took an in-app screenshot of the “card” and then shared it with the rest of the internet.

According to Jonathan, it started as a social experiment and basically let anyone buy a cup of coffee using his card and to tweet about the experience, and if possible to add a bit of money to the card. It’s a bit like those stores or restaurants where you pay according to how much you feel the product is worth to you, or it could even be compared to the honesty jar where you pay for your purchases without the need for a person to be present.

So far about $3,651 has been used which means there are tons of people out there who have been generous enough to top up the card.

I’ll admit, I thought Starbucks wouldn’t be too happy about the card sharing idea but it seems that they are pretty thrilled over the whole affair. I guess it’s free publicity for them. If you’re interested in participating in this little social experiment or just want a free cup of Starbucks, you can get the card at Jonathan Stark’s website.